This invention relates to dynamoelectric machines and, in particular, to a tool for installing a stator slide under a stator wedge in the stator core of a generator.
Dynamoelectric machines, such as generators, typically employ a stator or armature core comprised of stacked laminations of magnetic material forming a generally annular assembly. An array of axially extending circumferentially spaced stator core slots are formed through the radial inner surface of the annular assembly. Armature or stator windings are disposed in these slots. A rotor or field is coaxially arranged within the stator core and contains field windings typically excited from an external source to produce a magnetic field rotating at the same speed as the rotor. With the foregoing arrangement, it will be appreciated that electrical output is generated from the armature windings.
Stator or armature windings are seated within the stator core slots and are held in place by a slot support system that includes stator wedges, stator slides, filler strips and ripple springs. These support components are employed in order to maintain the stator armature windings in a radially tight condition within the slots. The armature windings of generators operate under continuous strain of electromagnetic forces that must be completely contained to prevent high voltage armature winding insulation damage. Insulation damage can also be exacerbated by relative movement between the armature windings and stator core. The wedges, slides, filler strips and ripple springs impose radial forces on the armature windings and aid the windings in resisting magnetic and electrically induced radial forces.
The stator wedges are received within axial dovetail slots on opposite sidewalls of the radial slots. During the process of tightening the stator wedges, it is necessary to install a stator slide against each stator wedge. For the sake of convenience, reference will be made herein to “stator wedges” that are seated in the dovetail slots and “stator slides” that are used to tighten the wedges. The stator slide can be, but is not necessarily, pre-gauged and pre-sized to have a significant interference fit relative to the slot contents, i.e., the windings, fillers and ripple springs. The force required to install the stator slide may be thousands of pounds.
Several methods have been used to provide the force required to install the stator slides. For example, stator slides have been manually installed using a drive board and a large hammer, or by using a modified pneumatically operated hammer. These methods, however, are time consuming and place considerable strain on the operator. They also subject the operator to fatigue, the risk of repetitive motion injury and/or hearing damage, and pose a risk to the integrity of the stator core and armature windings. The hammering technique can also cause snapped stator slides, which result from off-center hits, or an operator can inadvertently miss the slide and hit the stator core, resulting in damage to the core and a lengthy and time-consuming process to fix the damaged core portions. The uniformity and consistency of the stator wedge and stator slide tightness is also poor using the above-described methods.
Accordingly, a need exists in the art for a device that can be used to drive stator slides that minimizes operator fatigue and injury, minimizes stator core damage, minimizes installation time, and maximizes uniformity and consistency of stator wedge and stator slide tightness.